Surface microscopy and particulate adhesion
Abstract
Understanding the physics of particle adhesion and removal requires a broad knowledge base spanning areas of mechanical engineering, chemical engineering and material science. Previous studies on particulate adhesion have focused on simple geometric sets, with the primary emphasis concerning a spherical particle near a flat plate. Presented in this study is an investigation of the adhesion behavior of non-spherical particles and non-uniform surfaces. A three-pronged approach is used, with the goal of characterizing the primary adhesion force between a particle and a substrate. This primary force is the van der Waals force of adhesion. The first phase of the research is a theoretical investigation of the force of attraction and the energy of interaction between cylinders of infinite extent and particles of various shapes. These calculations indicate the relative importance of orientation between the particles and the surface; geometric sets that possess more intimate contact require more energy to separate. The second phase of research involves use of nanoindentation to characterize whether a model system (kaolinite/polyester) is susceptible to significant levels of adhesion-induced deformation. These results indicate that kaolinite may be considered to be mechanically similar to common polymers. The third phase of the study consists of direct force measurements between an AFM-mounted kaolinite particle and a polyester fiber. The measured pull-off force for the kaolinite/polyester system is sensitive to the composition of the surrounding medium and may be lowered by approximately one order of magnitude with an increase in system pH.
Degree
Ph.D.
Advisors
Goldschmidt, Purdue University.
Subject Area
Mechanical engineering
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